The steering and stability characteristics of motorcycles, bicycles, and other vehicles can be varied and altered in a number of different ways. Altering the front wheel assembly rake and trail angles can change the steering and stability characteristics of a vehicle. The rake angle is defined as the angle which the steering axis of the front wheel assembly of the vehicle, e.g., a motorcycle (often called the “neck” of the motorcycle frame), has relative to an imaginary vertical axis or plane. Thus, if an imaginary vertical plane is passed through the steering head assembly of a vehicle, the rake angle is that angle formed between such plane and steering axis of the front wheel assembly. The horizontal distance of the forward wheel's axle from a pre-defined measure is generally referred to as a vehicles's trail. The trail can also be described as the distance defined by a vertical line from the axle of the front wheel to the ground and the intersection of the line extending through the steering axis and the ground.
Variations in the rake angle and trail measurement of a vehicle will provide different ride and steering characteristics. Vehicle operators, builders, and customizers often extend the rake angle to obtain a desired look and desired performance. Vehicle rake and trail angles are precise measurements that depend, in part, upon, and are impacted by, the size of the front wheel of the motorcycle. Thus, if an operator, builder, or customizer desires to change the size of the front wheel, it is often necessary or desirable also to alter the rake angle of the vehicle to achieve the desired level of performance, stability, and safety. Additional rake is often preferred in order to secure the desired clearance between the front tire and the frame of the vehicle. With or without adding rake to the vehicle, vehicle operators, builders, and customizers will often stretch the steering axis forward for desired performance and/or aesthetic reasons, including, but not limited to, securing clearance between the vehicle's steering components and other structural components, such as the vehicle's frame, gas tank, ignition switch, or other controls. Various methods may be employed to alter the rake angle and stretch the steering axis, ranging from permanently modifying the vehicle frame, to installing raked triple trees, to installing adjustable kits.
Various methods of adjusting the front assembly of a vehicle, including extending the fork angle, are disclosed in U.S. Pat. Nos. 3,866,946, 4,082,307, 5,967,538, 4,565,382, 7,111,861, and 7,438,306, each of which is incorporated herein by reference in its entirety.
Many known designs and methods of adjusting the front assembly of a vehicle involve permanently or at least partially modifying the vehicle frame or other structure, which may adversely affect resale of the vehicle or the ability to further modify the vehicle, result in unintended or unpredictable vehicle performance or characteristics, and/or jeopardize a manufacturer's willingness to honor a vehicle warranty. Although certain known designs are capable of reversibly achieving the basic objective of adjusting the front assembly of a vehicle, they do so without adequate strength, security, and rigidity fully to resist the loads encountered by a motorcycle or other vehicle. Such deficiencies result in flexure of various portions of the assembly, especially of bolted members like mating surfaces of upper and lower plates and components joining the upper and lower plates. Further, locking or fixing features to prevent rotation or other movement between components of conventional designs are too small and often inadequately fitted to provide sufficient resistance to the loads applied. The net result of the combined strength and/or rigidity deficiencies described above results in a motorcycle or other vehicle having, at a minimum, poor handling, unreliable performance, and/or safety concerns.
Therefore, there exists a need for a vehicle raking assembly that is reliably, reversibly, and accurately applied to a motorcycle or other vehicle to obtain a desired altered steering rake angle. Further, there exists a need for a vehicle raking assembly having enhanced strength and rigidity to improve the handling and/or performance of the raked motorcycle or other vehicle, while still being reversible and removable, and not permanently changing the original steering rake angle.